Plastic bottle

ABSTRACT

A plastic bottle is provided with a constricted portion and a non-constricted portion contiguous above and below with the constricted portion. One of the constricted portion or the non-constricted portion has a substantially polygonal cross-sectional shape, and the other one of the constricted portion or the non-constricted portion has a circular cross-sectional shape.

TECHNICAL FIELD

The present invention relates to a plastic bottle for storing a liquid, such as a beverage or the like, and, in particular, relates to a plastic bottle that is easy to hold and minimizes the amount of resin used.

BACKGROUND ART

A large number of plastic bottles typified by PET bottles are sold as containers for filling with beverages. For example, JP2007-76717 discloses an example of a 500 ml bottle with improved ease of holding. In this bottle, a constricted portion is formed by constriction toward the center of a barrel portion, resulting in a shape that is easy for a consumer to hold, centered on this constricted portion. In order to maintain strength, a rib is arranged in the constricted portion.

Also, JP2005-247393 discloses a large 2 L size bottle. In this bottle, a barrel portion is formed with a rectangular cross-sectional shape, and a waist portion is formed at the vertical center portion of the barrel portion. This bottle also includes a concave finger insertion portion, which shares part of the waist portion.

Attempts have been made to improve bottle strength by adding liquid nitrogen prior to capping in order to place the interior of the bottle under a positive pressure. JP2006-137463 discloses an example of such a method.

Recently the reduction of bottle weight has advanced with the growing awareness of environmental problems. Disadvantages of reducing bottle weight by reducing wall thickness have included an overall reduction in bottle strength, such that bottles could not stand up to distribution, and could become extremely difficult for consumers to hold. The positive pressure used in JP2006-137463 may provide strength for distribution but, because the interior of the bottle returns to normal pressure after the cap is opened, the strength may be greatly reduced when the bottle is opened and holding the bottle may result in squeezing that could cause the contents to overflow out of the bottle.

SUMMARY OF THE INVENTION

An object of the present invention therefore is to provide a plastic bottle capable of assuring ease of holding and strength even when the bottle is reduced in weight, not only when the cap is closed, but also after opening.

In order to achieve the aforementioned object, a plastic bottle includes a constricted portion and a non-constricted portion contiguous above and below with the constricted portion. One of the constricted portion or the non-constricted portion has a substantially polygonal cross-sectional shape, and the other one of the constricted portion or the non-constricted portion has a circular cross-sectional shape.

The bottle, as compared to barrel portion with a cylindrical cross-sectional shape, is configured to have improved lateral and vertical strength in the barrel portion for a bottle having reduced weight. By furnishing the barrel portion with a part having a substantially polygonal cross-sectional shape, ease of holding the barrel portion can be improved, which may, for example, enhance the ease with which the cap may be opened and closed.

The constricted portion may have a substantially polygonal cross-sectional shape, and the non-constricted portion may have a circular cross-sectional shape. This may facilitate engaging a finger on the constricted portion, thereby improving the ease of holding of the constricted portion, which may, for example, improve the ease with which the cap may be opened. Moreover, an advantage of the non-constricted portion having a circular cross-sectional shape is that it may facilitate handling in the manufacturing process. Strength of the constricted portion can also be assured even in bottles in which the basic cross-sectional shape of the barrel portion is circular.

In some embodiments, the constricted portion may have a concave circumferential rib in a position at the vertical center of the constricted portion. This may permit a significant increase in the strength of the constricted portion by combining the substantially polygonal cross-sectional shape and the circumferential rib.

In addition, the circumferential rib may have a circular cross-sectional shape. This may result in a cross-sectional shape which, in order starting from the vertical center of the constricted portion, is circular, substantially polygonal then circular, thereby greatly improving the strength of the constricted portion and the barrel portion.

The constricted portion may have an upper polygonal surface above the circumferential rib and a lower polygonal surface below the circumferential rib. The upper polygonal surface and the lower polygonal surface may be formed in mutual vertical symmetry centered on the circumferential rib. The upper polygonal surface and lower polygonal surface respectively have approximately polygonal cross-sectional shapes, and are inclined toward the circumferential rib on the inside of the barrel portion. This may permit the alleviation of stress concentration between the upper polygonal surface and lower polygonal surface and the circumferential rib.

In some embodiments, the upper polygonal surface and the lower polygonal surface may include first and second surfaces repeating and alternating in the circumferential direction, wherein the first surfaces incline toward the inside of the barrel portion at an angle different from that of the second surfaces. This may improve the strength of the upper polygonal surface and the lower polygonal surface.

In some embodiments, the upper polygonal surface and the lower polygonal surface may respectively connect to the upper edge and lower edge of the circumferential rib by a gradually changing surface. This permits a smooth connection between the polygonal cross-sectional shape and the circular cross-sectional shape.

The upper polygonal surface and the lower polygonal surface may respectively have concave circumferential ribs. This may result in further strengthening of the upper polygonal surface and the lower polygonal surface. The cross-sectional shape of this circumferential rib may be circular.

In some embodiments, the cross-sectional shape of the upper polygonal surface and the lower polygonal surface may be in the shape of a dodecagon.

In some embodiments, the constricted portion comprises a deepest portion that is most constricted, an upper polygonal surface, and a lower polygonal surface. The upper polygonal surface and the lower polygonal surface may be formed in mutual vertical symmetry centered on the deepest portion. The upper polygonal surface and the lower polygonal surface may respectively have an approximately polygonal cross-sectional shape and may be inclined toward the deepest portion at the inside of the barrel portion.

Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a plastic bottle according to a first embodiment;

FIG. 2 is a right side view of the plastic bottle in FIG. 1;

FIG. 3 is a plan view showing an expansion of the constricted portion of the plastic bottle in FIG. 1;

FIG. 4 is a cross-sectional view of the plastic bottle in FIG. 1, taken at line IV-IV in FIG. 1;

FIG. 5 is a cross-sectional view of the plastic bottle in FIG. 1, taken at line V-V in FIG. 1;

FIG. 6 is a cross-sectional view of the plastic bottle in FIG. 1, taken at line VI-VI in FIG. 1;

FIG. 7 is a longitudinal-sectional view of the plastic bottle in FIG. 1, taken at line VII-VII in FIG. 1;

FIG. 8 is a longitudinal-sectional view of the plastic bottle in FIG. 2, taken at line VIII-VIII in FIG. 2;

FIG. 9 is a plan view of a plastic bottle according to a second embodiment;

FIG. 10 is a right side view of the plastic bottle in FIG. 9;

FIG. 11 is a longitudinal-sectional view of the plastic bottle in FIG. 9, taken at line XI-XI in FIG. 9;

FIG. 12 is a longitudinal-sectional view of the plastic bottle in FIG. 9, taken at line XII-XII in FIG. 9; and

FIG. 13 is a cross-sectional view of the plastic bottle in FIG. 9, taken at line XIII-XIII in FIG. 9.

DETAILED DESCRIPTION Exemplary Embodiments

The discussion below, refers to the attached Figures, and describes plastic bottles according to exemplary disclosed embodiments.

Exemplary Embodiment 1

As shown in FIGS. 1 and 2, a plastic bottle 1 is formed by a stretch forming method such as biaxial stretch blow molding, using a thermoplastic resin such as polyethylene, polypropylene, or polyethylene terephthalate as a primary material. An exemplary version of bottle 1 may have a weight of approximately 18 g, a height of approximately 200 mm, and a fully filled capacity of approximately 570 ml.

Bottle 1 may be washed and sterilized after molding, then filled with a beverage. Exemplary beverages that may be contained in bottle 1 include water, green tea, oolong tea, juice, and other non-carbonated beverages. In general, the internal pressure in the bottle is negative with non-carbonated beverages, making bottle strength weak. To provide strength, concave rib(s) may be formed on the disclosed bottle. For example, in embodiment 1, bottle 1 may have concave ribs 11-18 described below and may, therefore, be appropriate for filling with a non-carbonated beverage. In some cases, however, the liquid filled into bottle 1 may also be a carbonated beverage (e.g., soft drinks) or a food product such as sauce or the like.

The following are definitions of some of the terms used herein. Top and bottom (and up and down) are defined using FIG. 1, with the top of the page on which FIG. 1 is printed being “up” and the bottom of the page being “down.” The vertical direction means the direction along a center axis Y-Y of bottle 1. Height means the length along center axis Y-Y. Cross-sectional shape means the sectional shape of the bottle 1 in a plane (cross-section plane) perpendicular to center axis Y-Y. Circumferential direction means the direction along the profile of the cross-sectional shape. Radial direction means the direction extending radially from any point on center axis Y-Y in a direction perpendicular to center axis Y-Y.

In order starting from the top of center axis Y-Y, bottle 1 has a mouth portion 2, a shoulder portion 3, a barrel portion 4, and a bottom portion 5. These parts (2, 3, 4, and 5) may be integrally formed and constitute the walls of a bottle for storing a beverage therein. The center of gravity of bottle 1, when holding a drink in a filled state, may be located at center axis Y-Y.

Mouth portion 2 may be open at the top end and function as a pour spout for drinks. The opening of mouth portion 2 may be opened and closed using a cap (not shown). Shoulder portion 3 may have a circular cross-sectional shape, which gradually expands from the top to the bottom of shoulder portion 3. The bottom edge of shoulder portion 3 may be connected to a concave rib 11. Bottom portion 5 may be formed by a bottom wall 21 and a perimeter wall 22. Perimeter wall 22 may be a cylindrical part which stands upright so as to open upward from the perimeter of bottom wall 21. The top edge of perimeter wall 22 may be connected to a concave rib 18.

Barrel portion 4 may extend vertically between shoulder portion 3 and bottom portion 5. Barrel portion 4 may comprise a constricted portion 41 and non-constricted portions 42 and 43 connected to the top and bottom of constricted portion 41. Constricted portion 41 may be a section of barrel portion 4 that is constricted, and may be positioned slightly below the vertical center portion of bottle 1. Constricted portion 41 may be positioned slightly below the center of gravity of bottle 1 when filled with a beverage. This may permit easy tilting and stable handling of bottle 1 when a consumer drinks a beverage by holding the constricted portion 41. Constricted portion 41, given its shape, may also be referred to as the “waist” portion.

Non-constricted portions 42 and 43 may be cylindrical sections with a circular cross-sectional shape forming the maximum outer diameter of bottle 1. The upper non-constricted portion 42 may extend in the vertical direction without constrictions, and may be formed with multiple, circumferential, concave ribs 11,12,13, 14, and 15. The lower non-constricted portion 43 may extend in the vertical direction without being constricted, and may also be formed with multiple, circumferential, concave ribs 16, 17, and 18. The cross-sectional shape of concave ribs 11-18, although shown as circular, could have any shape that reinforces strength. The strength (particularly the radial strength) of non-constricted portions 42 and 43 may be reinforced by ribs 11-18.

As shown in FIGS. 3 through 6, constricted portion 41 may be formed so that its cross-sectional shape is substantially a dodecagon, with 12 sides. As described below, while the cross-sectional shape of constricted portion 41 maintains an essentially 12 sided shape, it does change in the vertical direction. Therefore, the cross-sectional shape was described as substantially a dodecagon. Although, a dodecagon is shown and described as an exemplary cross-sectional shape that may be used for constricted portion 41, other polygons such as a hexagon, octagon, or decagon could be used.

As shown in FIG. 3, constricted portion 41 may include upper and lower polygonal surfaces 52 and 53, formed in mutual vertical symmetry centered about a circumferential rib 51. Circumferential rib 51 may be located at a vertical center position of constricted portion 41, and may be the deepest portion, (i.e., the most constricted) of constricted portion 41. The strength at the vertical center of constricted portion 41 may be reinforced by circumferential rib 51. Circumferential rib 51, as shown in FIG. 4, may be a concave rib with a circular cross-sectional shape, and may have the smallest diameter of barrel portion 4.

The polygonal surfaces 52 and 53 may be respectively formed so as to gradually expand in diameter with vertical distance from circumferential rib 51. As shown in FIG. 5, polygonal surfaces 52 and 53 may have approximately dodecagonal cross-sectional shapes.

As shown in FIGS. 3, 5, and 6, the cross-sectional shape of polygonal surfaces 52 and 53 may be formed in such a way that an approximately dodecagonal shape approaches the shape of a circle with distance from circumferential rib 51. In other words, the cross-sectional shape of polygonal surfaces 52 and 53 may be formed so that the polygonal corners are the most angular nearest to circumferential rib 51 (as shown in FIG. 5), and the polygonal corners become gradually more rounded with distance from circumferential rib 51 (as shown in FIG. 6). In light of the fact that the circumferential rib 51 is formed in the position at which the corners are most angular, polygonal surfaces 52 and 53 in the present embodiment connect with the top and bottom edges of circumferential rib 51 via surfaces 55 and 56, which gradually change in the vertical direction. By this means polygonal surfaces 52 and 53 and circumferential rib 51 may be smoothly connected.

As shown in FIG. 3 and FIG. 5, polygonal surface 52 may include 6 each of first surfaces 61 and second surfaces 62 alternately positioned about bottle 1. Polygonal surface 53 may include the same configuration of surfaces as that of polygonal surface 52 and, therefore, a detailed description of polygonal surface 53 is not provided herein.

As shown in FIG. 5, first surface 61 may have a greater circumference than second surface 62 in the vicinity of the circumferential rib 51. At the same time, as shown in FIG. 3, first surface 61 may be formed to be shorter than second surface 62 where it is distant from circumferential rib 51. As shown in FIGS. 7 and 8, first surface 61 and second surface 62 may be inclined, on the inside of constricted portion 41, toward circumferential rib 51 at mutually differing angles. More particularly, between circumferential rib 51 and a circumferential rib 71, first surface 61 may be inclined at a smaller angle with respect to the cross-section than is second surface 62. The same may be true between circumferential rib 51 and a circumferential rib 72. Hatch marks in the cross-section section have been omitted from FIGS. 7 and 8 for purposes of clarity.

As shown in FIGS. 3 and 6, circumferential ribs 71 and 72 may be concave ribs formed on polygonal surfaces 52 and 53, and may each have a circular cross-section. The position of circumferential ribs 71 and 72 is not particularly limited. In some embodiments, circumferential ribs 71 and 72 may be positioned at any location where reinforced strength is desired, such as at the vertical center of polygonal surfaces 52 and 53, as shown. The height between circumferential rib 71 and circumferential rib 72 may also be not particularly limited. In some embodiments, this height may correspond, approximately, to the width of a single finger. By using this size, a consumer may be able to easily place his or her finger between ribs 71 and 72 when holding constricted portion 41.

According to bottle 1 of the embodiment explained above, the cross-sectional shape of barrel portion 4 may be basically round like non-constricted portions 42 and 43, while only constricted portion 41 has an approximately 12 sided polygonal shape. Therefore even with an overall round bottle shape, the radial strength of the constricted portion 41 as a whole can be improved, as can vertical strength. Radial strength can also be obtained for non-constricted portions 42 and 43 using concave ribs 11-18. Because the cross-sectional shape of barrel portion 4 is arranged in this way, weight reduction of the bottle 1 can be achieved through reducing wall thickness and the like, while assuring strength. This strength can also be assured after the cap has been opened. Exemplary specifications for bottle 1 according to embodiment 1 may include a weight of approximately 18 g and a capacity of approximately 570 ml, with a quotient of weight (PF gauge) divided by capacity being greater than or equal to 20 and less than or equal to 50.

Circumferential ribs 51, 71, and 72 may be formed so that the strength of constricted portion 41 may be reinforced. In particular, the cross-sectional shape of constricted portion 41 may alternately repeat in an order starting from the vertical center as follows: round (circumferential rib 51), approximately 12 sided (polygonal surfaces 52 and 53), round (circumferential ribs 71, 72), and approximately 12 sided (polygonal surfaces 52 and 53). Because of this alternating round and polygonal structure, a synergistic effect may be realized, and strength may be greatly improved. Since polygonal surfaces 52 and 53 may incline on the inside toward circumferential rib 51, the concentration of stress between polygonal surfaces 52 and 53 and circumferential rib 51 can be ameliorated compared to the case in which the polygonal surfaces 52 and 53 extend in parallel to center axis Y-Y. Moreover, an even greater strength improvement can be achieved due to the differing inclination angles of polygonal surfaces 52 and 53 between first surface 61 and second surface 62.

Because the cross-sectional shape of constricted portion 41 may be approximately dodecagonal, opening and closing of the cap can be more smoothly accomplished compared to a circular shape. In addition, because a consumer's finger engages easily with constricted portion 41, bottle 1 can be easily held. Thus, according to embodiment 1, bottle 1 may permit ease of holding and assure strength when weight is reduced, as well as suppressing the deformation caused by external pressures such as gripping force or the like.

Exemplary Embodiment 2

FIGS. 9 through 13 illustrate a bottle 100 according to a second embodiment. The main point of difference vs. embodiment 1 discussed above is the constitution of the constricted portion. Below we assign the same reference numerals to those parts of embodiment 2 which are the same as in embodiment 1.

Bottle 100 may include a constricted portion 110, which may have an approximately dodecagonal cross-sectional shape. The cross-sectional shape is described as “approximately” dodecagonal for the same reason as explained above with respect to embodiment 1. In other embodiments, the cross-sectional shape of constricted portion 110 may approximate polygons other than a dodecagon. Unlike constricted portion 41 in embodiment 1, embodiment 2 does not include circumferential ribs formed on constricted portion 110.

Constricted portion 110 may have upper and lower polygonal surfaces 112 and 113 centered around a most-constricted, deepest portion 111. As shown in FIG. 13, the cross-sectional shape of deepest portion 111 may be approximately dodecagonal. The cross-sectional shape of polygonal surfaces 112 and 113 may be formed so that the approximately dodecagonal shape approaches a circle as it gets farther away from deepest portion 111 (see FIGS. 9 and 10).

Polygonal surfaces 112 and 113 may contain 6 each of a first surface 121 and a second surface 122 repeating and alternating in a circumferential direction about bottle 100. As shown in FIGS. 9 and 10, one of the first surface 121 and second surface 122 becomes longer in the circumferential direction in proximity to deepest portion 111 and the other becomes longer in the circumferential direction with distance from deepest portion 111. And as shown in FIGS. 11 and 12, first surface 121 and second surface 122 may be inclined inward toward deepest portion 111 at mutually differing angles. Note that the cross-section hatch marks have been omitted from FIGS. 11 and 12 for purposes of clarity.

Constricted portion 110 of bottle 100 may be provided with no circumferential rib, and may, therefore, have less transverse strength than bottle 1 in embodiment 1. However, even if bottle 100, as a whole, is a “round bottle,” the overall radial strength and vertical strength of constricted portion 110 may be improved because the cross-sectional shape of barrel portion 4 may be non-uniform in the same way as in embodiment 1.

Since constricted portion 110 may have an approximately dodecagonal cross-sectional shape, bottle 100 may be easy to hold for consumers, which may, for example, facilitate smooth opening and closing of a cap thereon. Therefore, ease of holding and strength can be assured in bottle 100 even when weight is reduced, not only when the cap is closed, but also after it is opened.

As discussed above, in both embodiment 1 and embodiment 2, constricted portions 41 and 110 may have an approximately polygonal cross-sectional shape, and non-constricted portions 42 and 43 may have a circular cross-sectional shape. Other embodiments, however, may include a constricted portion with a circular cross-sectional shape and non-constricted portions with an approximately polygonal cross-sectional shape.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims. 

1. A plastic bottle, comprising: a barrel portion having a constricted portion and a non-constricted portion contiguous above and below with the constricted portion, wherein one of the constricted portion or the non-constricted portion has a substantially polygonal cross-sectional shape, and the other one of the constricted portion or the non-constricted portion has a circular cross-sectional shape.
 2. The plastic bottle of claim 1, wherein the constricted portion has a substantially polygonal cross-sectional shape, and the non-constricted portion has a circular cross-sectional shape.
 3. The plastic bottle of claim 2, wherein the constricted portion has a concave circumferential rib at a vertical center position thereof.
 4. The plastic bottle of claim 3, wherein the cross-sectional shape of the circumferential rib is circular.
 5. The plastic bottle of claim 3, wherein the constricted portion includes an upper polygonal surface above the circumferential rib and a lower polygonal surface below the circumferential rib; wherein the upper polygonal surface and the lower polygonal surface are formed in mutual vertical symmetry centered on the circumferential rib; and wherein the upper polygonal surface and the lower polygonal surface respectively have substantially polygonal cross-sectional shapes, and are inclined on an inner side of the barrel portion toward the circumferential rib.
 6. The plastic bottle of claim 5, wherein the upper polygonal surface and the lower polygonal surface both include first and second surfaces alternately repeating in the circumferential direction, wherein the first surfaces incline toward the inside of the barrel portion at an angle different from that of the second surfaces.
 7. The plastic bottle of claim 5, wherein the upper polygonal surface and the lower polygonal surface respectively connect to the upper edge and lower edge of the circumferential rib by gradually changing surfaces.
 8. The plastic bottle of claim 5, wherein the upper polygonal surface and the lower polygonal surface respectively have circumferential ribs.
 9. The plastic bottle of claim 2, wherein the constricted portion includes: a deepest portion that is most constricted; an upper polygonal surface; and a lower polygonal surface, wherein the upper polygonal surface and the lower polygonal surface are formed in mutual vertical symmetry centered on the deepest portion, and wherein the upper polygonal surface and the lower polygonal surface respectively have substantially polygonal cross-sectional shapes, and are inclined on an inner side of the barrel portion toward the deepest portion. 